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The New Process Roller Mills - also, what powers Abbotts Mill?

Continued from last week - Thomas H. Coursey (1805-1999) began milling as a young man at what is now called Wyoming Mill, although the mill was there before the town of Wyoming even existed. After saving his money for a few years he was able to purchase the old "Spring Mills" on the Murderkill River, where Coursey's Pond is now. He eventually became a prolific writer of letters to the editor of the (Wilmington) Morning News, the forerunner of The News Journal. In the following letter, he has been writing about his life as a miller, and how he has tried to keep up with the competition:


I kept pace with the times until... when roller mill flour came into competition. There is no denying the fact that roller mill flour is whiter than burr flour [flour from mill stones], but when that is said, all is said. The burr flour is more healthy, sweeter, stronger, and the bread will keep moist from twelve to twenty-four hours longer than roller flour bread. Fresh bread from roller flour is very nice, but when it is a few hours old it becomes dry and chaffy, and is no comparison to bread of the same age from burrs.


But the people have a white flour craze. Mrs. Jones saw Mrs. Brown’s bread made from roller mill flour, and she determines that the bread on her table shall be as nice as Mrs. Brown’s, and Mrs. Smith is not to be behind Mrs. Jones, and so it goes from one to another. White bread from roller mill flour looks nicer. The old time burr mill is the more healthy. It is the kind our fathers and forefathers lived on way back to the early ages. Old Mr. Methusalah and the old gentlemen who lived in his day and counted their years by the hundreds never heard of the roller mill. Their bread was made from flour manufactured from the whole wheat ground between stones, on the principle of the present day, and we have no evidence that they had even a sifter to take out the course bran. They certainly had no No. 16 bolting cloth. Physicians of the present day recommend to persons of weak digestion bread made from flour made from the whole wheat without removing the bran. This only goes to show that the old time flour is the most healthy.


Now I am not going to run a tilt against roller mills, for I may have one myself if I have many more years to live, not from choice but from necessity. Competition drives men sometimes to do what they would rather not do. But I, at the same time, think that roller mill outside the spring wheat region have been rather a curse than a blessing. They have rendered almost valueless millions worth of property that was paying good interest. If the flour was more healthy we would have some compensation, but it is not. I heard an eminent physician who now owns a roller mill, say that roller mill flour was not fit to raise children on. If unfit for children, it cannot be equal to the other for grown folks. But the people are resolved to have white flour, health or no health, and those millers who are driven to change will have to sink the present value of their mills in arranging a complication of rolls, scalpes, conveyors, purifiers, aspirators, centrifugals, and an endless array of elevators, bolts and other jimcracks that will necessitate another apprenticeship to milling. Mills of the present day are using No. 16 cloth; then we used No. 8. We are using in our mill No. 12. It seems hardly possible that there can be as much change in the next fifty years.

T. B. Coursey, Spring Mills, Del. March 3, 1885


I think than many millers felt the same way that Mr. Coursey felt. They knew how to produce a very fine grade of flour and cornmeal with their "burr mills," and they saw no reason to go to the trouble and great expense to install the new roller mill process. That is, until another nearby mill installed it and Mrs. Brown started buying her flour there. And so it went, from one mill to another. And remember from last week, it isn't just the roller mills that need to be purchased and installed.


In the case of Abbotts Mill, then owned by William and Alfonza Hendricks, it was necessary to build an entirely new 3 1/2 story addition to the existing mill, with 10 new elevators, a new separator, a bolter, a scourerer, many new storage bins, and a new flour packer, as well as the drive shaft, pulleys and belts to power it all, All this to produce an all-white flour with little nutritional value.


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So how are the rollermills powered at Abbott's Mill?


The first dam that Nathan Willey built, circa 1800, was likely not as high as the present dam, which is about 8 feet high. I think Mr. Willey’s waterwheel very likely was of the undershot type, meaning that the wheel was powered only by the force of the water flowing under it. However, by the time the present mill was built, sometime in the mid-1800s, the dam had probably been added to and the increased height (head) made a breastshot wheel feasible, which then provided a little more power. The three types of waterwheel most commonly found in mills are; undershot, breastshot and overshot.

The following descriptions of the different types of waterwheels are used with permission from Waterwheel Manufacturing, Inc. in Frankin, North Carolina.


Undershot Waterwheel

This type of waterwheel relies on the flow of water coming along the base at a good rate of speed to push or thrust the waterwheel. This type of waterwheel is used on mills built on streams that do not have any height (or head). Undershot wheels are normally narrow and have to have the channel walls very close to the sides of the wheel to maximize the flow of water to pass through the wheels to generate power. This type of wheel is generally the least efficient type of wheel - usually in the 30-50% range.

The Overshot Waterwheel

The overshot wheel is a gravity wheel. This means that it harnesses the force of gravity acting vertically on the water as it travels from the top to the bottom of the wheel.

The overshot wheel is most effective when it turns as slowly as possible and can still handle the total flow of water available to it. The optimal rim speed should be only about 3 feet per second. The larger the wheel the slower it will need to turn. The incoming water must be traveling about three times the rim speed of the wheel so that it can fill the buckets effectively. This requires a foot or more of head above the wheel, usually controlled by a gate.

To prevent dragging during a flood period the wheel must be mounted at least a foot above the tail water. The buckets start spilling water well before reaching the bottom. This along with the sacrifice of two or more feet of head above and below reduces the efficiency of the wheel to 70-90%.


The Breastshot Waterwheel

When the head, or fall of water was not sufficient for a large diameter overshot wheel, the breast wheel often is used. This is halfway between the overshot and undershot wheels. Water strikes the buckets of the breast wheel about midway between top and bottom, using the weight of the water for a 90-degree segment of arc. While more efficient than the undershot, their efficiency is far less than the overshot, which uses the weight of the water for a full 180 degrees. © Waterwheel Manufacturing, Inc. 2022


So, why isn’t there a waterwheel at Abbott’s Mill now? I have found no written record, yet, of what may have happened to the waterwheel, or when it happened. However, we do have a piece of it. This chunk of iron that was found in the tailrace a few years ago is the gudgeon pin that fit in the outboard end of the waterwheel axle and rested on a hardwood bearing block.


See a similar gudgeon in the bottom-left corner of the below drawing.


We also have two undated photographs that were found in Mr. Abbott’s files. They were taken during a flooding event and they clearly show the part of the mill where the waterwheel would have been, and it’s obvious that they were taken before the turbine had been installed.


The waterwheel would've been under that shed roof. If you zoom in, I almost think you can see it in there.

There are red-painted siding boards on the inside wall of that shed-roofed room, meaning that the waterwheel had not always been covered. Judging by the size of the room, the breastshot waterwheel would've been 8 to 10 feet wide and about 12 feet or so in diameter.


Checking old newspaper records for the worst flooding events in this area between 1927 (when the engine room was built) and 1963 (when Mr. Abbott retired) turns up a storm known as the 1933 Chesapeake–Potomac hurricane that hit this area on August 23rd and caused severe damage throughout the Mid-Atlantic region. Rainfall in nearby Bridgeville reached 13.24 inches and in Milford the dam at the railroad bridge on Silver Lake was sandbagged to strengthen it. The danger was so great that, at the height of the storm, officials checked with Ainsworth Abbott every half hour to make sure his dam was holding. Had it failed, the flood of water down Johnson’s Branch and the Mispillion River could have caused a domino effect on the dams on Haven Lake and Silver Lake, destroying much of downtown Milford.


I think that that’s when the above pictures were taken and that the storm did enough damage to the penstock and water wheel that Mr. Abbott took the opportunity to replace them with a water turbine. Perhaps he already knew where a used one was that he could acquire. I’m sure it wasn’t a decision he took lightly, as it required replacing that entire end of the basement, where the exposed timbers are (above), with a large cast-in-place concrete turbine well. It looks to me like it was all done in a single pour, which would not be an easy undertaking, even today. But, on the plus side, he no longer had to deal with the maintenance of the waterwheel. Wooden waterwheels required constant upkeep by the miller.

The concrete turbine well is the light-colored area just to the left of the brickwork. It has a clean-out hatch in the middle of it.

Mr. Abbotts records also indicate that he bought a lot of what he called "sinders" (cinders) for fill material for his dam in the seven years after 1933, I think that would've been either to repair flood damage, or to increase the height of the dam.

In place of the waterwheel, Mr. Abbott installed a cast-iron turbine, which was never intended to power the entire mill, but just the two 48" stone "burr" mills.



That's the turbine down there, normally under 6 1/2 feet of water.

The movable vanes around the circumference can be opened to allow water to spin the turbine inside. Notice the water cascading down in the background. In operation that whole well is 6 1/2 feet deep in water.

Ever since 1925, the roller mills have been powered by a 20 hp diesel engine. We'll take a look at the engine next week, but if you would like to see it running, stop by for our Visitor's Center OPEN HOUSE tomorrow (Sept. 9th) between 2:00 and 4:00 p.m. and it'll be chugging away in the mill. Sorry, but the rest of the mill is still closed.

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Next week: Mr. Abbotts HUGE 20 hp Fairbanks-Morse semi-diesel engine. How did he get it here from West Virginia?

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